Crate pmcp_code_mode_derive 

Derive macro for Code Mode validation and execution in MCP servers.

Provides #[derive(CodeMode)] which generates a register_code_mode_tools method that registers validate_code and execute_code tools on a [pmcp::ServerBuilder].

Field Name Convention (v0.1.0)

The macro identifies required fields by fixed well-known names. This is the v0.1.0 contract – the field names are the API:

Field Name	Required Type	Purpose
code_mode_config	CodeModeConfig	Validation pipeline configuration
token_secret	TokenSecret	HMAC signing secret
policy_evaluator	Arc<dyn PolicyEvaluator> or Arc<P>	Policy evaluation
code_executor	Arc<dyn CodeExecutor> or Arc<E>	Code execution

If any required field is missing, the macro emits a single compile error listing all absent fields.

Struct-Level Attributes (v0.2.0)

Attribute	Type	Default	Purpose
context_from	String	(none)	Method name returning ValidationContext
language	String	"graphql"	Selects validation path and tool metadata

Supported language values:

Value	Validation Method	Feature Required
"graphql" (default)	validate_graphql_query_async	(none)
"javascript" / "js"	validate_javascript_code	openapi-code-mode
"sql"	validate_sql_query	sql-code-mode
"mcp"	validate_mcp_composition	mcp-code-mode

When context_from is specified, register_code_mode_tools requires self: &Arc<Self> and the generated handler calls self.parent.{method}(&extra) to obtain real ValidationContext bound to the current user/session.

When context_from is omitted, register_code_mode_tools uses &self (no Arc required) with placeholder context values and a #[deprecated] warning guiding users toward the production path.

Generated Code

The macro generates:

1. A register_code_mode_tools method on the struct that takes a ServerBuilder by value and returns it (by-value fluent pattern).
2. Two internal handler structs (ValidateCodeHandler and ExecuteCodeHandler) that implement pmcp::ToolHandler.
3. A Send + Sync compile-time assertion (per D-08).

Examples

Production (with context_from):

#[derive(CodeMode)]
#[code_mode(context_from = "get_context", language = "graphql")]
struct MyServer {
    code_mode_config: CodeModeConfig,
    token_secret: TokenSecret,
    policy_evaluator: Arc<NoopPolicyEvaluator>,
    code_executor: Arc<MyExecutor>,
}

impl MyServer {
    fn get_context(&self, extra: &RequestHandlerExtra) -> ValidationContext {
        ValidationContext::new("user-1", "session-1", "schema-v1", "perms-v1")
    }
}

// Generated: MyServer::register_code_mode_tools(self: &Arc<Self>, builder) -> ServerBuilder

Testing (without context_from, deprecated placeholder path):

#[derive(CodeMode)]
struct MyServer {
    code_mode_config: CodeModeConfig,
    token_secret: TokenSecret,
    policy_evaluator: Arc<NoopPolicyEvaluator>,
    code_executor: Arc<MyExecutor>,
}

// Generated: #[deprecated] MyServer::register_code_mode_tools(&self, builder) -> ServerBuilder

Derive Macros

CodeMode

Derive macro that generates register_code_mode_tools for Code Mode servers.